Good news for Obamacare? Mass. reforms might be saving 320 lives a year.

Health-care reform in Massachusetts might be responsible for saving 320 lives per year, according to a paper published Monday that credits the state’s implementation of universal health coverage in 2006 with a marked decrease in statewide death rates.

The new research, published in Annals of Internal Medicine, supplies some of the first analysis of the effect of universal health care on longevity, and its results offer optimism for President Obama’s 2010 Affordable Care Act. Major parts of the president’s program are based on Massachusetts’ 2006 health-care law, which mandated that everyone in the state get health insurance and vastly expanded the poor’s access to Medicaid.

“Our findings add to a growing body of evidence showing that health insurance makes a positive difference in people’s lives,” said Benjamin Sommers, assistant professor of health policy and economics at Harvard School of Public Health and the lead author of the study, in a statement.

“How closely the impact of the Affordable Care Act will mirror the Massachusetts’ experience is something we’ll have to continue watching closely, but this is certainly encouraging news for the law’s potential impact on public health,” said Professor Sommers, who is also a part-time adviser at the US Department of Health and Human Services, which has headed the planning and rollout of Obamacare.

One death per year was prevented for every 830 adults who gained access to health care after 2006, saving about 320 lives per year, according to the paper. Overall, among adults between 20 and 64 years old, death rates in the Bay State dropped by 2.9 percent between 2007 and 2010, compared with a four-year period before the law was passed, the researchers reported. Mortality rates measure the number of deaths per 100,000 people.

In particular, the state saw fewer deaths from diseases that doctors say are less likely to be fatal if caught early during regular health-care visits, including infections, cancer, and heart disease, the researchers said. Deaths from these diseases “amenable to health care” went down 4.5 percent, according to the paper.

The decline in the death rate was highest in Massachusetts’ poorer counties and among populations who were uninsured before the law was passed, the paper said. The improvement was twice as great for minorities as it was for whites, the researchers found.

The researchers did not find any change in death rates for Massachusetts residents above 65 years old, the paper said.

Massachusetts’ death rate was also compared with the rate in similar populations without a universal health-care law. In 513 counties in 46 states that did not have such a law, mortality rates did not change over the same period, the researchers found.

“Reform in Massachusetts was associated with a significant decrease in all-cause mortality compared with the control group,” the authors write.

Previous, smaller studies on the influence of state health-care reform on death rates have been inconclusive, but experts on Tuesday praised the most recent paper – by researchers at Harvard University’s School of Public Health in Boston – as offering perhaps the most comprehensive look yet at the influence of universal health care on death rates.

“In the hierarchy of evidence, this ranks way above everything we’ve seen in the past in terms of the effects on mortality,” David Meltzer, a health economist at the University of Chicago who was not involved in the research, told The New York Times.

Still, the paper’s authors caution, the research shows just a correlation between Massachusetts’ health-care reform and lowered death rates, and it does not definitively show that health reform caused mortality rates to ebb.

The Massachusetts law is popularly known as “Romneycare,” so named after Mitt Romney, the state’s governor at the time. Though other states have flirted with health-care reform, introducing a number of statewide changes, Massachusetts is so far the lone state to undergo a complete overhaul, extending coverage to almost everyone, according to the Times.

Should Obamacare replicate Massachusetts’ success, resulting in a national 3 percent decline in adult death rates, that would translate into about 17,000 fewer deaths a year, according to the Times. Government statistics show that more than 8 million people have so far signed up for health insurance under Obamacare, exceeding expectations for sign-ups, despite the troubled rollout.

Experts note, though, that Massachusetts’ experience might not be transferable to other states, since the Bay State, richer and whiter than most states, is generally recognized as able to offer a higher quality of health care to consumers than can most parts of the United States.

“I would be surprised if we didn’t see a closing of the gap that could be attributed to improved coverage rates,” Barbara Ferrer, executive director of the Boston Public Health Commission, told WBUR.

But, she told the public radio station, “We have to be a little bit wary, that you can’t just insure people without making sure that they have access to high-quality services. But certainly in Massachusetts we’re able to do both.”